The Special Report on Land use, Land-use Change, and Forestry (IPCC, 2000a)
estimated a significant potential for increasing carbon stocks in the agricultural
sector. Improved management of cropland and grazing-lands, agroforestry, and
rice paddies have the potential to sequester 398 MtC annually, and the conversion
of cropland to agroforestry practices and grasslands can sequester an additional
428 MtC annually by 2010. These estimates are highly uncertain, however, and
do not include the impact on the net emissions of methane (CH4) or
nitrous oxide (N2O) from agricultural practices or wetlands and/or
permafrost management.

CH4 emissions from agriculture produce about eight per cent of the
radiative forcing of all GHGs (Watson et al., 1996). CH4 from manure
can be captured and used for fuel; emissions from ruminants can be reduced with
better diets, feed additives, and breeding; and emissions from rice paddies
can be mitigated by nutrient management, water management, altered tillage practices,
cultivar selection, and other practices (Mosier et al., 1998).

Many of the mitigation options to address these opportunities may provide multiple
benefits to the farmer and society at large. Improving soil management for crop
production, for instance, can also improve water relations, nutrient retention,
and nutrient cycling capacity (Paustian et al., 1998). Retiring surplus agricultural
lands can result in improved water quality, reduced soil erosion, and increased
wildlife habitat. As Izac (1997) points out, however, farmers, who will be the
ultimate decision makers about which mitigation option to adopt, have shorter
planning horizons than national or international beneficiaries, and many mitigation
options ask them to bear costs up front while the benefits are longer term and
to the society at large.

Furthermore, in order to realize these opportunities a very large proportion
of farmers who pursue diverse agricultural practices will have to be convinced
to adopt mitigation options. Economic, cultural, and institutional barriers
exist which restrict the rate of adoption of such practices. Farmers who are
accustomed to traditional practices may be reluctant to adopt new production
systems. Crop price supports, scarcity of investment capital, and lack of economic
incentives for addressing environmental externalities are some of the economic
barriers. Limited applicability of mitigation options to different types of
agriculture, negative effects on yield and soil fertility for rice production,
and the increased skilled labour requirements are some of the other constraints.
Among these barriers the especially critical ones are highlighted here.

Farm-level Adoption Constraints
Several generic constraints characterize the adoption of most new agricultural
technology. These include small farm size, credit constraints, risk aversion,
lack of access to information and human capital, inadequate rural infrastructure
and tenurial arrangements, and unreliable supply of complementary inputs. Participatory
arrangements that fully engage all the involved actors may help to overcome
many of these barriers.

Government Subsidies
Subsidies for critical inputs to agriculture, such as fertilizers, water supply,
and electricity and fuels, and to outputs in order to maintain stable agricultural
systems and an equitable distribution of wealth can distort markets for these
products. These types of subsidies prevail in both developed and developing
countries. Low electricity prices in India, for example, provide a disincentive
for the use of efficient pump sets, and encourage increased use of ground water,
which depletes the water reservoirs. In the OECD, for example, high levels of
farm subsidies have also contributed to the intensification of farm practices
and often provide incentives to increase fertilizer use, livestock density,
etc. (Storey, 1997).

Lack of National Human and Institutional Capacity and Information in the
Developing Countries
Several of the Consultative Group on International Agricultural Research (CGIAR)
systems are experiencing difficulty as their funding slows. The systems have
not transferred capacity to national centres in the developing countries that
they are expected to serve. The national centres also lack access to information,
and are not aware of technologies that suit their local conditions (IPCC, 2000b).

Intellectual Property Rights
To some extent the reduced public funding on new technologies has been replaced
by the private sectors contribution. Private sector funding offers one
approach to increasing investment for mitigation projects worldwide. Private
plant breeding research has more than quadrupled in the USA in real terms between
1970 and 1990. Its international role is, however, controversial. Protection
of intellectual property rights is weak, especially for commercially developed
seed varieties (Deardorff, 1993; Frisvold and Condon, 1995, 1998; Knudson, 1998).
On the other hand, hybridization will help to stimulate more investment from
the private sector at the risk of increasing the farmers dependency on
the annual purchase of new seeds. There are also concerns that genetic resources
that have not been considered as privately-owned intellectual property may get
patented worldwide by private investors.

Several measures may be pursued to address the above barriers. These include

The expansion of internationally supported credit and savings schemes,
and price support, to assist rural people to manage the increased variability
in their environment (Izac, 1997);

Shifts in the allocation of international agricultural research for the
semi-arid tropics towards water-use efficiency, irrigation design, irrigation
management, and salinity, and the effect of increased CO2 levels
on tropical crops (Tiessen et al., 1998);

The improvement of food security and disaster early warning systems, through
satellite imaging and analysis, national and regional buffer stocks, improved
international responses to disasters, and linking disaster food-for-work schemes
to adaptation projects (e.g., flood barricades);

The development of institutional linkage between countries with high standards
in certain technologies, for example flood control; and

The rationalization of input and output prices of agricultural commodities
taking DES issues into consideration which would lead to more efficient use
of input resources.